This invention relates to doorbells and in particular to a two chime doorbell that is operated by a solenoid mechanism.
A typical prior art solenoid operated doorbell is illustrated in FIGS. 1 and 2 as having first and second solenoids 10 and 11 and first and second chimes 12 and 13. Each solenoid has a support spring arranged to coact with its armature. Thus, support spring 11a is arranged to coact with armature 11b of solenoid 11 such that when energized, the armature 11b will be impelled downwardly to strike chime 13. Upon deenergization of the solenoid the spring drives the armature upward where it strikes the second chime. This results in a two-tone ring consisting of the sequential striking of the chime bars 13 and 12.
The other solenoid 10 is arranged to operate identically to solenoid 11. However, the ringing of the upper chime 12 is inhibited by the placement of a damper pad 14 above the solenoid 10 so that its armature strikes the damping pad 14 rather than the chime 12. This assures that only one chime (chime 13) will ring when solenoid 10 is energized.
FIG. 2 illustrates a simple circuit for operation of the doorbell from a voltage supply 15. This circuit includes a first circuit branch having a switch S1 and the coil 11c of solenoid 11 connected in series with the supply and a second branch consisting of a switch S2 and the coil 10C of solenoid 10 also connected in series with the supply.
This prior art doorbell has been a successful commercial product, known in the trade as Builders' Chime Kits, Catalog No. C210, available from Edwards Company, Inc. of Farmington Conn. It is to be noted that the doorbell trade is extremely competitive such that any improvement in price or manufacturing cost is highly advantageous, particularly if the doorbell provides the same single and double tone ringing operations.